首先，我们要明确一下，40岁的男士可能会面临一些身体问题，比如肌肉减少、骨骼松弛等，这些都可能导致肩膀变得不那么结实和宽阔。要想解决这个问题，我们需要制定一个合理的训练计划。
以下是一些建议的训练动作：
（1）侧平举：两脚开立，同臂下垂，双手握拳或手持重物，然后同臂侧平举，让手臂与肩部保持水平位置3-4秒，再还原。每组12-15次，练习3组。
（2）俯卧撑：要求俯撑时肘外展，并保持两肘与肩在一水平线上。每组10-12次，练习3组。
（3）屈臂提肘：两腿开立，上体前屈，上臂向后拉至上臂与地面水平，同时保持肘部外展并维持3秒再还原。
这些动作可以帮助我们增强三角肌，即位于肩部皮下的一块多羽状肌，它们是决定我们双肩宽度的关键肌肉群。而影响我们的三角肌中束大小的一个主要因素就是我们的三角肌中束的维度大小，因为它位于身体两侧，对于视觉效果有很大的影响。
为了达到最佳效果，每个人都应该根据自己的实际情况来调整训练计划，不仅要考虑到具体执行动作的方法，还要注意饮食和休息，以便更好地促进身体恢复。此外，要记得耐心，一切好的东西都是慢慢积累起来的，不用急于求成。
Shoulder training for a 40-year-old man: How to make your shoulders wider
As we age, our bodies undergo changes that can affect our muscle mass and bone density. For men in their 40s, these changes may lead to narrower shoulders. But with the right exercises and a consistent routine, it's possible to widen your shoulders.
Here are some exercises you can try:
(1) Lateral Raises: Stand with feet shoulder-width apart, arms hanging down at your sides. Hold dumbbells or weights in each hand and raise them out to the sides until they reach shoulder height. Lower them back down slowly and repeat for 12-15 reps per set.
(2) Push-ups: Start in a plank position with hands shoulder-width apart. Lower your body until your chest almost touches the ground, then push back up to the starting position.
(3) Bent Over Rows: Hold onto something sturdy like a chair or barbell while standing on one leg (or both legs if needed). Bend over forward slightly and let one arm hang straight down from shoulder level while keeping elbow locked into place. Slowly lift weight up towards opposite hip by bending elbow as much as possible before lowering it back down again.
These exercises target different parts of the deltoids muscles which are located below the skin around our shoulders. They play an essential role in determining how wide or narrow our shoulders appear from outside perspective.
To get optimal results consider tailoring workout plans based on individual physical abilities along with proper nutrition intake & sufficient rest periods allowing faster recovery process overall progress will be more noticeable over time due diligence is key when trying new workouts routines so don't rush anything patience is rewarded here too!